Bisphenol A (BPA) is strongly suspected as a human endocrine disrupter. We propose to follow up our earlier published preliminary report on the human reproductive toxicity of BPA among workers in four Chinese chemical plants. We expect to recruit (a) 300 current and former BPA-exposed workers (200 men and 100 women), (b) 300 spouses, for examining intermediate exposure levels, and (c) 300 offspring, for examining multigenerational effects. For each male worker, two controls with no history of exposure to BPA will be selected from local textile factories. Because of the smaller number of exposed female workers, four controls will be selected per exposed female worker, thus 800 controls with their spouses and offspring will be recruited. Our specific aims are as follows: (1) Among women (both exposed workers and spouses of male exposed workers), is there a relationship of exposure with sex hormone profile, menstrual disorders, frequency of sexual intercourse, time-to pregnancy, and spontaneous abortion? (2) Among men (both exposed workers and spouses of female exposed workers), is there a relationship of exposure with sex hormone profile, inhibin B levels, semen quality, and frequency of sexual intercourse? (3) Among the children of exposed workers, is there a relationship of parental exposure with sex ratio, birth weight, age at development of secondary sex features, menstrual characteristics, and sex hormone profile? Current BPA exposure will be obtained from air sampling through personal monitoring. Cumulative exposure will be estimated through a semi-quantitative job/exposure matrix. An in-person interview will be conducted to obtain detailed information on work history, reproductive and sexual history, and the age at puberty of offspring. Blood and semen samples will be evaluated for hormone levels and semen quality. The work will be conducted by the Shanghai Institute of Planned Parenthood Research and Fudan University (formerly Shanghai Medical University), Department of Occupational Health in collaboration with University of Washington. They have extensive experience in the data collection and lab analysis methods that will be used in the study. The proposed study will evaluate the reproductive effects of BPA in settings where there have been high levels of exposure. The study will also investigate effects in multiple human generations.